Objective

To investigate the outcomes of mixed-grade non-muscle invasive bladder cancer (NMIBC) based on the degree of high-grade predominance.

Methods

We identified patients in our institutional database who had a transurethral resection of bladder tumor(s) for NMIBC. Tumors with mixed-grade features on pathology report were reanalyzed, assigned the percentage high-grade component, and stratified into ≤ 5% high-grade and > 5% high-grade groups. All others were classified as low-grade or high-grade NMIBC. Differences in recurrence-free survival were assessed by log-rank test. A multivariable Cox regression model was used to evaluate the impact of tumor grade on recurrence, controlling for tumor stage, size, multifocality, and intravesical therapy.

Results

Two hundred and twenty patients were followed for a median of 2 years; 127 (58%) had low-grade NMIBC, 66 (30%) had high-grade NMIBC, and 27 (12%) had mixed-grade NMIBC. Of the mixed-grade patients, 14 had a ≤ 5% high-grade component, and 13 had a > 5% high-grade component. Recurrence rates across all groups ranged from 42% to 79%. There was no significant difference in intravesical recurrence-free survival among the grade categories as assessed by log-rank test. On multivariable Cox regression analysis, grade category was not significantly associated with likelihood of recurrence.

Conclusions

The prognosis of mixed-grade histology in NMIBC has not previously been well defined. Although grade category was not found to be an independent significant predictor of recurrence, the recurrence rate for mixed-grade tumors was quite high overall. Further studies are required to better understand appropriate risk stratification and treatment of mixed-grade NMIBC.

中文翻译：

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肿瘤分级异质性对非肌层浸润性膀胱癌复发的影响

客观的

研究基于高度优势程度的混合级别非肌肉浸润性膀胱癌 (NMIBC) 的结果。

方法

我们在我们的机构数据库中确定了为 NMIBC 进行了经尿道膀胱肿瘤切除术的患者。重新分析病理报告中具有混合分级特征的肿瘤，分配高级别成分的百分比，并分层为≤5% 高级别和> 5% 高级别组。所有其他被归类为低级或高级 NMIBC。通过对数秩检验评估无复发生存率的差异。多变量 Cox 回归模型用于评估肿瘤分级对复发的影响，控制肿瘤分期、大小、多灶性和膀胱内治疗。

结果

对 220 名患者进行了中位随访 2 年；127 人（58%）为低级别 NMIBC，66 人（30%）为高级别 NMIBC，27 人（12%）为混合级别 NMIBC。在混合级别的患者中，14 名患者的高级别成分≤5%，13 名患者的高级别成分>5%。所有组的复发率从 42% 到 79% 不等。通过对数秩检验评估的等级类别之间的膀胱内无复发生存率没有显着差异。在多变量 Cox 回归分析中，等级类别与复发的可能性没有显着相关性。

结论

NMIBC 中混合级别组织学的预后以前尚未明确定义。尽管未发现分级类别是复发的独立显着预测因子，但混合分级肿瘤的总体复发率相当高。需要进一步研究以更好地了解混合级别 NMIBC 的适当风险分层和治疗。